G protein-coupled receptor of lysophosphatidylserine (LysoPS) that plays different roles in immune response (PubMed:36823105). Plays a negative role in regulatory T-cell accumulation and homeostasis. Under inflammatory conditions where LysoPS production increases, contributes to the down-regulation of regulatory T-cell activity to favor effector response. Mediates the suppression of IL-2 production in activated T-lymphocytes leading to inhibition of growth, proliferation and differentiation of T-cells. Mechanistically, acts via G(s)- containing heterotrimeric G proteins to trigger elevated cyclic AMP levels and protein kinase A/PKA activity, which may in turn act to antagonize proximal TCR signaling. Plays an important role in the initial period of sepsis through the regulation of macrophage polarization and pro- and anti-inflammatory cytokine secretions. Upon testosterone treatment, acts as a receptor for CCL21 and subsequently triggers through G(q)-alpha and G(12)/G(13) proteins a calcium flux leading to chemotactic effects on activated B-cells. Signals via GNA13 and PKA to promote CD86 up-regulation by follicular B-cells. . This is the function of ENSG00000147138 (GPR174, G protein-coupled receptor 174).